HOW DID THE dinosaurs DIE?

No single event caused the extinction of the dinosuars but two events contributed the most towards it these are:

The Deccan flats event 68 million yrs ago (massive flood basalt eruptions)

The meteor impact on the Yucatán Peninsula 66 million yrs ago in southeastern Mexico

It is not known if the dinosuars were in decline prior to those events but both events caused such catastrophic climate change that combined they eliminated all non-avian dinosaurs.
The usual idea that a single meteor impact wiped out all dinosuars over a period of a few years is false, the extinction of the dinosaurs took several millions of years.

The birds around us are the descendants of some of thsoe dinosaur species.

You can read more here:

ucmp.berkeley.edu/education/events/cowen1b.html

nhm.ac.uk/nature-online/life/dinosaurs-other-extinct-creatures/mass-extinctions/end-cretaceous-mass-extinction/index.html

bbc.co.uk/nature/extinction_events/Cretaceous%E2%80%93Tertiary_extinction_event